Influence of the Type of Fertilization on Nitrogen Balance of the Mountain Meadow

Piotr Kacorzyk, Miros ław Kasperczyk and Wojciech Szewczyk Department of Grassland Management, Institute of Plant Production, University of Agriculture in Krakow, Al. Mickiewicza 21, Krakow 31-120, Poland

Received: June 12, 2014 / Accepted: October 14, 2014 / Published: October 30, 2014.

Abstract: Among fertilizer ingredients nitrogen is the one noted for biggest losses because its susceptibility to volatilize to the atmosphere and to be leached away from the soil. These losses depend on the level and mode of fertilization. It appears that every year in Poland river waters transport to the Baltic Sea from the whole area about 180 thousand tons of the nutrient. The largest portion of this load is ascribed to agriculture. This study focused on the highland areas, which are commonly seen as a water supplying region owing to the fact that they cover about 35% of water need in the authors’ country. Specificity of grassland fertilization in these lands is high contribution of natural fertilizers including dunging with fresh manure left by penned animals, particularly by sheep. Authors decided to assess the influence of dunging by folded sheep on meadow nitrogen balance and on its concentration in percolating water. It was demonstrated that a nitrogen balance was highly negative for each object, so the grassland plants supplied their needs in large part with nitrogen from mineralization of soil organic matter. Relatively high loads of nitrogen leached out of the folded objects indicate that nitrogen from mineral fertilizers is better utilized by grassland herbage and thus is much safer for soil and water environment.

Key words: Water, nitrogen, environment, mountain meadow, folding.

1. Introduction  our country. Specificity of grassland fertilization in these lands is high contribution of natural fertilizers

Among fertilizer ingredients nitrogen is the one including dunging with fresh manure left by penned noted for biggest losses. They are caused by its animals, particularly by sheep. This manner of susceptibility to volatilize to the atmosphere and to be fertilization was already investigated in crop leached away from the soil [1-3]. These losses depend production aspect by some authors [5-7]. However, on the level and mode of fertilization. From the these studies did not consider the effect of such calculation done by Sapek [4] it appears that every fertilization upon soil environment, which may be year in Poland river waters transport to the Baltic Sea negative, especially for thin soils in mountains. This is from the whole area about 180 thousand tons of the the reason why the authors decided to assess the nutrient. The largest portion of this load is ascribed to influence of dunging by folded sheep on mountain agriculture. According to the aforenamed author meadow nitrogen balance and on its concentration in agriculture would contribute to nitrogen introduction

percolating water.

into natural environment at the level of about 70%. This study focused on the highland areas, which are

2. Materials and Methods

commonly seen as a water supplying region owing to The study was carried out from 2009 to 2011 on a the fact that they cover about 35% of water need in mountain meadow (N49º24'57.3899",

E20º55'32.2649", 613 m n.p.m.), the type of red Corresponding author: Piotr Kacorzyk, Ph.D., research field: mountain meadows. E-mail: p.kacorzyk@ur.krakow.pl.

fescue (Festuca rubra) and common bent grass

Influence of the Type of Fertilization on Nitrogen Balance of the Mountain Meadow

(Agrostis capillaris). An experimental field had the output were nitrogen quantity harvested with the yield brown soil classified by texture as loamy sand. The

of the plant mass and leached from the soil through soil was acid (pH KCl = 4.3), moderately rich in

percolating water.

potassium, while very poor in phosphorus. Five

3. Results

objects have been included in the research in three replications. Objects of study were: control and 4

Nitrogen (N-NH 4 +N-NO 3 ) concentration in liquid fertilized objects, including one with mineral precipitation per a vegetational season was at least fertilizers, two only with folding with the participation

two times lower than in a non-vegetational season of sheep and one with folding supplemented by

(Table 1).

mineral fertilization with nitrogen and phosphorus. However, nitrogen loads delivered to the soil Folding treatments were differentiated according to

surface during non-vegetational seasons were stock density into a low-density fold (1 sheep per 2 m 2 considerably higher, even though the total seasonal

for 2 nights) and a high-density fold (1 sheep per 1 m 2 rainfall for them averaged lower by a third when for 2 nights). The amounts of nutrients left in the

compared to the summer seasons (Table 1). Average

yearly nitrogen load reaching the soil surface in liquid low-density fold and P 28 K 294 N 184 kg/ha for a precipitation was about 16.3 kg/ha. high-density fold. Then in the case of inorganic

dunged objects would be P 14 K 147 N 92 kg/ha for a

Water outflow coefficients (the ratios of percolating fertilization minerals were applied yearly: phosphorus

water outflow to precipitation inflow) for vegetational and potassium as a single dose in spring, while

seasons were the lowest in the first, and the highest in nitrogen dose was supplied in two portions, 60% in

the second year of the experiment (Table 2). spring and 40% for 2nd regrowth. Folding was

In the former case these values varied between performed in spring 2009. The meadow was mowed

23.2% for control and 29.6% for inorganic

fertilization, while in the latter they ranged from 28% to evaluate nutrient utilization and the amount and

twice each year. The area of a plot was 50 m 2 . In order

for low-density folding to 38.9% for inorganic composition of percolating water each object was

fertilization. In non-vegetational seasons these fitted with 3 lysimeters at the depth of 40 cm (because

coefficients occurred to be considerably higher and the soil thickness was such). The amounts of water

less dependent on the level of fertilization. In the first passing through the soil profile were measured several

such period, 2009-2011, they ranged from 80.5% to times as it appeared over there. The amounts of

82.6%, whereas in the second 2009-2011, from 60.0% rainfall were evaluated using a Hellman pluviometer

to 63.5%.

located on the experimental field. The test cycle Total nitrogen concentration in water passing includes two periods: the growing season lasting from

through a 40 cm-deep soil profile differed April to September and the after-growing season

substantially in consecutive years of the experiment lasting from October to March. The levels of nitrogen

(Tables 3, 4).

uptake in harvested plant biomass and soil nitrogen In the first year respective values were the highest concentrations were determined using the Kjeldahl

for each object in both measuring periods. By contrast, method. By contrast nitrogen level in rainfall and

the lowest ones were found for water from a control effluent water were determined with and fertilized objects in the second year, whereas from microprocessor-controlled photometer LF205. In sheepfold objects in the third experimental year—the nitrogen balance input side included quantities of

last one. The range of fluctuations in water nitrogen fertilizers and atmospheric precipitation while the

content noted on average a triple decrease for control,

Influence of the Type of Fertilization on Nitrogen Balance of the Mountain Meadow

Table 1 Total precipitation, its nitrogen content and loads of nitrogen (N-NH 4 +N-NO 3 ) delivered with rainfalls.

Season

Item Vegetational Non-vegetational 2009 2010 2011 2009-2010 2010-2011 Total precipitation mm

N content (mg·dcm 3 ) 1.09 0.90 1.12 2.25 1.85

N load (kg/ha)

Table 2 Coefficient of rainfall water outflow (%).

Season

Treatment Vegetational Non-vegetational 2009 2010 2011 2009-2010 2010-2011 0—control 23.2 28.6 28.7 80.5 59.8 P 25 K 50 N 120 29.6 38.9 26.7 81.2 60.3

Folding density: Low-density: P 14 K 147 N 92 24.2 28.0 29.9 81.4 63.5 Low-density + P 10 N 50 25.3 34.9 28.9 80.2 62.4 High density: P 28 K 294 N 184 29.0 31.9 30.7 82.6 62.8 LSD (P = 0.05)

Table 3 Nitrogen (N-NH

4 +N-NO 3 ) content in percolating water (mg·dcm ).

Season

Treatment Vegetational Non-vegetational 2009 2010 2011 2009-2010 2010-2011 0—control 2.04 0.63 1.15 0.32 0.50 P 25 K 50 N 120 3.96 1.27 1.39 2.37 1.17

Folding density: Low-density: P 14 K 147 N 92 3.55 1.10 1.15 1.76 0.70 Low-density + P 10 N 50 6.31 1.89 0.90 5.08 0.77 High density: P 28 K 294 N 184 6.56 1.53 1.12 5.42 0.98

Table 4 Nitrogen (N-NH 4 +N-NO 3 ) content in percolating water (mg·dcm 3 ) in non-vegetational season.

2009-2010 2010-2011 Treatment

V% 0—control

mg·dcm 3 SD

1.17 0.67 57 Folding density:

P 25 K 50 N 120 2.37 1.23 52

Low-density: P 14 K 147 N 92 1.76 1.07 61

Low-density + P 10 N 50 5.08 2.84 56

High density: P 28 K 294 N 184 5.42 2.66 49

mineral fertilization and low-density folding objects, the fact that in the third year nitrogen concentration in and even a 6- to 7-fold decrease for a high-density

percolating water per each folded object occurred to sheepfold or for a low-density sheepfold plus

be similar to the control, and this value was fertilization. What deserves the authors’ attention is

considerably lower than the respective level for the

Influence of the Type of Fertilization on Nitrogen Balance of the Mountain Meadow

mineral fertilization object. regardless of fertilization treatment. Although in the As regards the loads of nitrogen leached from the

second and third year the highest amounts of nitrogen soil by percolating water this study showed a

were gathered with plant crop from the object relationship similar to that for nitrogen content (Table

fertilized with minerals. Then the next one was the 5).

low-density sheepfold supplied with minerals. By However, the level of nitrogen was slightly

contrast, the objects fertilized with the use of folding modified with different amounts of percolating water

alone yielded similar and distinctly lower amounts of among the objects, which was changing due to the

nitrogen in plants, and in the last year this value was plant species composition what has been presented in

even inferior to the control.

the earlier paper [8]. Yearly load of nitrogen leached From nitrogen balance analysis carried out after the with percolating water averaged about 3.5 kg/ha for

3-year experimental period differences between control, 10.8 kg/ha for mineral fertilization and 17.5

nitrogen input (in fertilizers and liquid precipitation) kg/ha for high-density folding, and the differences

and nitrogen output (in gathered plant crop and were significant statistically. Especially large nitrogen

percolating water) were found negative for each object loads were leached during the first year in both

(Table 7).

seasons from the high-density sheepfold and the low Here the lowest result of -212.1 kg/ha was achieved density sheepfold supplied with minerals. The by the control object, then followed by low-density respective amounts were 33.2 kg/ha for the former and

sheepfold, high-density sheepfold and low-density

29.3 kg/ha for the latter. Moreover, in these objects sheepfold with inorganic fertilizers. And the least the sum of nitrogen leached out in a winter season was

negative balance was obtained for mineral by one-third higher than in a vegetational season.

fertilization.

Nitrogen amount gathered with plant crop within a Finally, after 3 experimental years total nitrogen three-year period of meadow use reached maximum

concentration in a 10 cm deep surface soil for the object receiving inorganic fertilization alone

substantially decreased for each object (Table 8). The (Table 6).

most remarkable loss was noted for inorganic This value was by 60% higher as compared with the

fertilization and high-density folding, whereas the control, and by 21% higher than in both folding

lowest for low-density folding.

objects without mineral supplementation. In the first

4. Discussion and Conclusions

year an object delivering the largest measure of nitrogen was the high-density sheepfold, while the

Nitrogen input from atmospheric precipitation in other objects delivered nitrogen in similar quantities

this study (15.6-17.7 kg N/ha) is lower than the values

Table 5 Load of nitrogen (N-NH 4 +N-NO 3 ) taken away in percolating water (kg/ha).

Season

Treatment Vegetational Non-vegetational Total 2009 2010 2011 2009-2010 2010-2011 0—control 3.47 1.20 2.05 1.11 1.40 9.23 P 25 K 50 N 120 8.60 3.28 2.30 8.30 3.30 25.8 Folding density: Low-density: P 14 K 147 N 92 6.27 2.05 2.13 6.18 2.08 18.7 Low-density + P 10 N 50 11.7 4.38 1.61 17.6 2.25 37.5

High density: P 28 K 294 N 184 13.9 3.25 2.13 19.3 2.88 41.5 LSD (P = 0.05)

Influence of the Type of Fertilization on Nitrogen Balance of the Mountain Meadow

Table 6 Amount of total nitrogen (N) gathered with crop of grassland plants.

Treatment

(kg/ha)

0—control

88.1 53.0 242.1 P 25 K 50 N 120 148.0 155.0 85.0 388.0 Folding density: Low-density: P 14 K 147 N 92 152.0 104.9 48.1 305.0

Low-density + P 10 N 50 156.0 118.0 71.6 345.0

High density: P 28 K 294 N 184 180.9 105.1 48.1 334.1

Table 7 Nitrogen (N) balance after 3 years of experiment.

Difference Treatment

Gain from fertilizers and precipitation Loss with crop and percolating water

(kg/ha)

0—control 39.2

-212.1 P 25 K 50 N 120 399.2

-14.6 Folding density: Low-density: P 14 K 147 N 92 131.2

-192.5 Low-density + P 10 N 50 281.2

-102.0 High density: P 28 K 294 N 184 223.2

Table 8 Total soil nitrogen at the beginning and after 3 years of experiment.

Treatment % Initial condition

After 3 years: 0—control 0.26

P 25 K 50 N 120 0.25 Folding density: Low-density: P 14 K 147 N 92 0.30 Low-density + P 10 N 50 0.26 High density: P 28 K 294 N 184 0.25

that give other authors [9-11]. Instead, it is similar to of the soil to stop it. Given that nitrogen leached out the amount delivered with wet precipitation [12, 13].

of the control amounted to 4.6 kg/ha the relative This amount, however, was clearly higher than it

quotients of soil nitrogen runoff due to leaching as could be leached out of there by infiltrating water.

compared to nitrogen delivered with fertilization will Significantly higher ratios of rainwater outflow, and

be respectively 16% for the former and 17% for the nitrogen loads during winter season compared with

latter. However, for the inorganic fertilization this the growing period resulted from the lack of uptake of

percentage was only 10%. Highly negative nitrogen nutrients by plants. The highest nitrogen output in the

balances for almost all objects, except for the mineral cases of high-density folding, which took place in the

fertilized one, is reflected in a soil nitrogen decrease first year after fertilization treatment was probably

below the baseline level. After 3 years of the study results from too big dose of fertilizers or from a rapid

nitrogen concentration in 12 cm deep surface soil was mineralization of sheep manure and a small capacity

reduced by 0.01-0.06%. According to our data such a

Influence of the Type of Fertilization on Nitrogen Balance of the Mountain Meadow

12 cm deep surface layer of the soil weighs about

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Górskich za Pomoc ą Koszarzenia Cz. I. Skład Botaniczny all object. This indicates that the plants complement

i Plonowanie łąki.” Grassland Science in Poland 13: 77-84.

their needs of nitrogen from soil organic matter [9] Goulding, K. W. T. 1990. “Nitrogen Deposition to Land

mineralization. from the Atmosphere.” Soil Use and Manag. 6 (2): 61-63. Water outflow coefficients in the surface soil were

[10] Stadelmann, F. X. 1995. “Landesweite Nährstoffbilanz: positively correlated with the level of meadow

Terrestrische, Aquatische und Atmosphärische nitrogen fertilization.

Überforderung. W Wieviel Landwirtschaft braucht der

Greater loads of nitrogen (N-NH Mensch? Wissenschaftliche Tagung 22-24, Koresshaus

4 +N-NO 3 ) leached

Davos. Erich, ETH 12: 1-11.

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(Suppl. 1): 305-311.

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Journal of Life Sciences 8 (2014) 835-840

doi: 10.17265/1934-7391/2014.10.007

DAVID PUBLISHING

Effect of Phosphonate Fertilizers on the Growth of Soil Fungi

1 2 2 Samer Samir Mohd Habash 3 , Mohammad Saleh Al-Bess , Ahmad Saleh Al-Bess and Luma Shareef AL Banna 1. INRES-Molecular Phytomedicine, University of Bonn, Karlrobert-Kreiten-StraBe 13, Bonn 53115, Germany

2. Department of Research and Development, Al-Qawafel Agro-Industrial Establishment, Amman 11194, Jordan 3. Department of Plant Protection, Faculty of Agriculture, University of Jordan, Queen Rania Street, Amman 11942, Jordan

Received: January 23, 2014 / Accepted: October 30, 2014 / Published: October 30, 2014.

Abstract: The phosphonate fertilizers, Calphos ® (calcium phosphonate), Magphos ® (magnesium phosphonate) and Phosphoros ® (potassium phosphonate) were used in Jordan and showed a nematicidal effect. This study aimed to investigate the fungicidal effect of these fertilizers against the growth of the fungi, Fusarium proliferatum, Altrenaria solani, Pythium debaryanum and Penicillium digitatum. Results showed that the phosphonate fertilizer Calphos ® at the concentration of 1% mixed with potato dextrose agar (PDA) totally inhibited the growth of all studied fungi. Magphos ® (1%) delayed the growth of the fungus F. proliferatum and inhibited the growth of other tested fungi. While Phosphoros ® (1%) mixed with PDA inhibited the growth of A. solani and P. digitatum even after

12 d of incubation and delayed the growth of F. proliferatum and P. debaryanum compared with the growth of the fungi on the PDA only.

Key words: Phosphonate, Fusarium, Alternaria, Pythium, Penicillium.

1. Introduction  fungus, Penicillium digitatum causes a pre and post harvest fruit rot of several crops making their fruits

Species of Fusarium and Pythium are soil unmarketable [3]. Therefore, populations of these inhabitant fungi that infect wide range of host plants. pathogens should be suppressed to enhance crop Fusarium proliferatum is such a species that exhibits production. The incidence and severity of diseases wilting of several vegetables, fruit trees, and caused by F. proliferatum and P. debaryanum can be ornamentals [1, 2]. The infected plants may eventually significantly suppressed by using the integration of die and the production will be significantly reduced. clean soil, seeds, or seedlings [4-5]. However, it is On the other hand, Pythium debaryanum is one of the more difficult to suppress such diseases if the field is causal agents that are responsible of pre and post infested. On the other hand, the reduction of the emergence damping off of several economic plants [3]. Alternaria spots and Penicillium fruit rots can be The high incidence of damping off will reflect achieved by foliar application of fungicides. significantly the return. Carbamates such as Thiocarbamates, and The foliar fungus, Alternaria solani is considered organophosphate such as Pyrazophos, are fungicides one of the most important pathogens of foliar diseases. used commonly to suppress the fungal diseases. This fungus attacks leaves, stems and fruits causing Because of the risk and the toxicity of fungicides to spots and early blight of infected crops, thus reducing the environment and the limitation of using soil quantity and quality of the produce. The green mold solarization and fumigants, alternative means should

be used and not only that but also should be integrated Corresponding author: Luma Shareef AL Banna, Ph.D.,

associate professor, research fields: plant pathology, with other control means. Such alternative is the nematology. E-mail: lalbanna@ju.edu.jo.

Effect of Phosphonate Fertilizers on the Growth of Soil Fungi

application of some fertilizers that showed and 6% magnesium as magnesium phosphonate. The suppressive effects against plant pathogenic fungi. ® third fertilizer, Phosphoros , includes 3% nitrogen,

Recently in Jordan, liquid fertilizers containing 27% phosphorus as P 2 O 5 , 18% potassium as K 2 O, and phosphonate group were used to enhance plant growth.

mono and dipotassium phosphonate. Phosphonates, sometimes called phosphites, are salts

2.1.2 Fungal Isolates

of phosphorous acid or phosphonic acid that are Isolates used in this study belong to F. proliferatum, relatively inexpensive, apparently environmentally

P. debaryanum, A. solani, and P. digitatum were benign and provide durable control of root rot and

isolated from crops grown in different regions. The dieback in cut flowers and forest species [6-7]. It has

isolate of F. proliferatum was recovered from palm been also reported that phosphorus as phosphonate

trees grown in the southern part of Jordan at Al group has fungicidal effect on a wide range of fungi

Qweirah. Whereas, the fungus P. debaryanum was [8-12]. It was reported that the use of low isolated from cucumber infected plants grown under concentration of Phosphorus acid inhibited the plastic houses in the Jordan valley. Isolates of A. mycelial growth and the sporangium formation of two

solani and P. digiataum were obtained from the species of Phytophthora, P. cinnamomi and P.

department cultures. The fungi plated and maintained citricola [13]. Similarly, the microconidial production

on Potato Dextrose Agar (PDA) and incubated at of three Fusarium isolates was reduced after exposure

25 ºC ± 2 ºC for further tests.

to phosphonate [11]. Recently, Habash and Al-Banna [14] showed that

2.2 Methods

the phosphonate fertilizers, Calphos ® , Magphos ® and

2.2.1 Treatments

Phosphoros ® had a nematicidal effect against two root PDA media were used and mixed with the knot nematodes, Meloidogyne javanica and M.

fertilizers at a 1% concentration (1 mL of the fertilizer incognita. In this study, the authors aimed to investigate

was added to 99 mL PDA) and autoclaved then plated the fungicidal effect of the three phosphonate in 9 cm diameter Petri dishes. The pH of the PDA fertilizers, Calphos ® , Magphos ® and Phosphoros ® on

alone or mixed with fertilizers was measured and the growth of the fungi, F. proliferatum, A. solani, P.

tabulated (Table 1).

debaryanum and P. digitatum.

2.2.2 Effect of Fertilizers on the Fungal Growth

2. Materials and Methods

Approximately 5-mm-diameter plugs of each fungus inoculum were cut by using a cork borer (0.5

2.1 Materials cm in diameter) from the margins of the fungal

2.1.1 Fertilizers cultures. Each plug was placed in the centre of 9 Three locally manufactured phosphonate fertilizers,

cm-diameter plastic Petri plates containing PDA

Calphos ® , Magphos and Phosphoros , were used in mixed with the studied fertilizer at 1% concentration. this study and were supplied by the local fertilizer ® Treatments were PDA mixed with Calphos , PDA

company “Al-Qawafel IND.AGR.EST”. These locally mixed with Magphos ® and PDA mixed with manufactured phosphonate fertilizers were Phosphoros ® . Plates with PDA only served as a investigated for their potential fungicidal activities.

control. Each treatment was replicated three times. Calphos ® fertilizer includes 36% phosphorus as

Petri dishes were incubated at 25 ºC ± 2 ºC and were phosphonate and 6% calcium as calcium phosphonate.

checked periodically up to 12 d. The growth initiation Magphos ® fertilizer includes 19% phosphorus as

time and the diameter of the fungal growth were phosphonate, 6% potassium as potassium phosphonate

recorded for every replicate and were tabulated.

Effect of Phosphonate Fertilizers on the Growth of Soil Fungi

Table 1 The pH of the PDA treated with fertilizers.

with Magphos ® totally inhibited the growth of P. Fertilizer pH debaryanum (Fig. 1 (2A and 2B); Table 3) even after PDA with Calphos ® (1%)

1.20 12 d. On the other hand, the fungus grew on the PDA PDA with Magphos ® (1%)

2.83 mixed with Phosphoros ® after 3 d and the diameter of PDA with Phosphoros ® (1%)

5.85 the growth reached 3.8 cm after 12 d (Table 3). PDA only

5.13 On contrary the isolate of F. proliferatum initiated its growth one day after inoculation and reached its

3. Results

maximum growth on PDA plates after 12 d. Calphos ® Results showed that the growth of A. solani on

treatment totally inhibited the fungal growth even PDA plates only started after one day of treatments

after 12 d of treatment. The Magphos ® treatments and increased to cover the whole Petri dish after 12 d

postponed the fungal growth after 7 d while the fungal of inoculation on the PDA only (Table 2, Fig. 1D). ® growth started after 4 d on the Phosphoros treatment

However, no growth was observed on the plates of (Table 4). The fungal growth after 12 d of incubation PDA mixed with the phosphonate fertilizers even after

reached 1.3 and 3 cm on plates amended with

12 d (Fig. 1 (1A, 1B and 1C); Table 2). Magphos ® and Phosphoros ® respectively. The fungal growth of P. debaryanum on PDA only

The growth of P. digitatum was scattered and plates was initiated after 2 d of inoculation and was

almost covered the PDA Petri plate (Fig. 1 (4D)), fully covered the surface of the PDA only treatment

while all phosphonate fertilizers totally inhibited the after 8 d (Table 3). The PDA mixed with Calphos ® or

fungal growth (Fig. 1 (4A, 4B and 4C)).

Table 2 Effect of phosphonate fertilizers on the growth of Alternaria solani.

Diameter of the fungal growth (cm) after Treatment

Time of fungal growth initiation

12 d PDA with Calphos ® (1%)

4d 10 d

0 0 0 PDA with Magphos ® (1%)

No growth

0 0 0 PDA with Phosphoros ® (1%)

No growth

0 0 0 PDA only

No growth

1d 3 5.4 9 *Means of three replicates, diameters in cm.

Table 3 Effect of phosphonate fertilizers on the growth of Pythium debaryanum.

Diameter of the fungal growth (cm) after Treatment

Time of fungal initiation

4d 6d 8d 12 d

PDA with Calphos ® (1%) No growth

0000 PDA with Phosphoros ® (1%) 3 d 0.9 1.7 2.8 3.8 PDA only

PDA with Magphos ® (1%) No growth

2d 3.1 5.2 9 9 *Means of three replicates, diameters in cm.

Table 4 Effect of phosphonate fertilizers on the growth of Fusarium proliferatum.

Diameter of the fungal growth (cm) after Treatment

Time of fungal initiation

4d 6d 8d 12 d PDA with Calphos ® (1%) 0 0000

PDA with Magphos ® (1%) 7 0 0 0.2 1.3 PDA with Phosphoros ® (1%)

4 0 2 2.2 3 PDA only

1 3.7 5.7 6.8 9 *Means of three replicates, diameters in cm.

Effect of Phosphonate Fertilizers on the Growth of Soil Fungi

F. sporotrichioides and F. equiseti grew well at pH ranged from 3.3 to 10.4. Khilare and Rafi [16] also mentioned that the best pH level for sporulation of Fusarium oxysporum f. sp. ciceri is ranged from 6 to

6.5. Furthermore, they showed that the range from 4.5 to 8 is suitable for the Fusarium growth while foremost acidic and alkaline pH is not suitable. Oritsejafor [17] in his study approved that F. oxysporum f. sp. elaeidis couldn’t survive in the soil with pH equal to 3.

All phosphonate fertilizers inhibited the growth of

A. solani even after 12 d after incubation. These

2cm 2cm

results agreed with Van Bruggen et al. [18] study

Fig. 1 The effect of phosphonate fertilizers on the growth of fungi. A): PDA mixed with Calphos ®

where they indicated that the germination of the

conidia of A. solani decreased with the increasing of mixed with Magphos ® , C): PDA mixed with Phosphoros ®

(1%), B): PDA

(1%) and D): PDA only on the growth of 1) Alternaria

the acidity. Arunakumara [19] also showed that A.

solani, 2) Pythium debaryanum, 3) Fusarium proliferatum

solani prefers a range of pH from 6.5 to 7 for its

and 4) Penicillium digitatum after 12 d of incubation.

growth.

4. Discussion The P. digitatum growth was totally inhibited after

treatment with phosphonate fertilizers. Several studies The authors’ study showed that the fertilizers

proved that the pH value affects the growth and contained phosphonate compounds either inhibited or

germination of Penicillium spp. spores. Li et al. [20] delayed the growth of the studied fungi. The inhibition

showed that the optimum pH level for P. expansum effect varied between the studied fertilizers. The

spores germination is 5. While the spores germination fungicidal effect of these fertilizers might be related to

was inhibited at pH 2 and 8. Wheeler et al. [15] on the their pH. The pH of PDA mixed with Calphos ® or

other hand reported that P. crustosum tolerated the Magphos ® were 1.20 and 2.83 respectively and totally

acidic pH and grew on pH ranged from 3.3 to 10. inhibited the growth of the studied fungi. While the

These findings indicated that the effect of pH varied pH of PDA mixed with Phosphoros ® increased to 5.85

among the Penicillium spp.

and the inhibition effect decreased compared to other In addition to the effect of pH, the fungicidal effect fertilizers. The pH of PDA alone was 5.13 and didn’t

of the studied phosphonate fertilizers might be inhibit the fungal growth compared with Phosphoros ® resulted from the existence of the phosphonate

(main component potassium phosphonate). compounds in their formulation. Several studies

The phosphonate fertilizers, Calphos ® or Magphos supported this assumption and approved the fungicidal with pH 1.20 and 2.83, respectively inhibited the

effect of the phosphonate. Coffey and Joseph [13] growth of Fusarium proliferatum, while Phosphoros ®

approved that low concentration of Phosphorus acid inhibitory effect was less than the other two inhibited the mycelial growth of both Phytophthora phosphonate fertilizers. These results were supported

cinnamomi and P. citricola. Pankhurst et al. [8] also with the study of Wheeler et al. [15] which showed

showed that potassium phosphonate showed a broad that Fusarium sporotrichioides and F. equiseti growth

spectrum activity as a fungicide. Potassium varied with changing the pH and also they found that

phosphonate application as soil drench reduced the

Effect of Phosphonate Fertilizers on the Growth of Soil Fungi

infection of medicago roots by several fungi which environmental conditions are variable when compared belong to Fusarium spp., Phoma spp., Pythium spp.,

to laboratory assays.

and Rhizoctonia solani. Zainuri et al. [9] found that

Influence of the Type of Fertilization on Nitrogen Balance of the Mountain Meadow